A novel theoretical model for mass transfer of hollow fiber hemodialyzers

Hemodialyzers have been applied to hemodialysiswidely. In order to get accurate mass transfer coefficient and clearance to determine treatment time, their masstransfer models have been studied deeply. The domesticstudy on hemodialyzers is later, focuses on experiment, and seldom refers to theoretical mechanism[1,2], but theoverseas research is more in-depth. Simple one-dimensional models have been used to simulate mass transfer in hemodialyzers by many re-searchers[3—7]. Their models assumed …     

A novel theoretical model for mass transfer of hollow fiber hemodialyzers

A novel theoretical model for mass transfer of hollow fiber bundles in hemodialyzers is presented. In the model, a hemodialyzer is considered as a porous zone which is composed of two non-interpenetrating porous flow zones.Firstly, the dialysate side (shell side) is thought as a porous medium zone. Then by solidifying the dialysate flow zone and the occupied zone by hollow fiber membrane, the rest zone of bemodialyzer (i.e. blood side or lumen side) is considered as a porous medium zone too. Finally, the interface of the two flow zones is the fiber membrane through which mass transfer is performed. The dialysate and blood flows are all described by Navier-Stokes equations with Darcy momentum source terms. Kedem-Katchaisky equations as other source terms are added into Navier-Stokes equations to simulate the permeating flux through the membrane. All equations must be coupled together in the process of computing. The model is validated by the experimental data in literature. The simulative results show that the predicted clearances agree well with the experimental data, and the model in this paper is better than other models for the forecast of clearance.     

红细胞压积对血液透析器传质性能的影响

从理论和实验两方面研究了红细胞压（Ｈｃｔ）对ＳＴ１５中空纤维透析器尿素清除率的影响，结果表明，在临床范围内，Ｈｃｔ的变化（Ｈｃｔ＝０．２－０．４）仅影响血液测传质阻力和而对总传质阻力及溶质清降率影响较小，此外还讨论了提高中空纤维透析器溶质甭除率的可能窗径以及Ｈｃｔ对较大分子（肌酐，尿酸）清除率影响的特点及理论研究方法。